Kill everyone. Fallout style.

I have whole scene grid battles set up (scenes are fairly small + prerendered (Fallout1/2 style)). I have a combatant spawner in the "Field" which spawns Always Aggressive enemies, enter enemy range detection = show grid and start battle. That all works fine.I then changed over too "Aggressive when Attacked", I then call the battle menu via a script in the field and can attack an enemy if in range, which in turn will check combatant.isAggressive == true via script then start the battle grid system.

What would be the best way to do it? Have every NPC as Combatant's and have "aggressive when attacked" selected? With that method I would have to do away with the built in Faction system as I cant start battles with Allies( Could use Makinom global var's to make own sorta faction system)?

Basically, I need to be able to pull up battle menu (turn based), and attack anyone in range (friend or foe) that in turn will start grid battle. Similar to fallout style!